The invention sets forth in this specification pertains to new and improved dispensing closures. More specifically this invention pertains to unitary dispensing closures in which a lid is mounted upon a closure part or base such as is normally adapted to be secured to a container in such a manner that the lid may be manipulated between open and closed positions, and in which as a result of the construction employed the lid will tend to automatically move toward either an open or closed position when it is released after having been manipulated to any position between these two positions. Dispensing closures of the type described in the preceding discussion are sometimes referred to as "snap action" closures.
As a result of economic considerations increasing numbers of users of dispensing closures appear to desire to utilize one-piece, unitary dispensing closures instead of two-piece dispensing closures in which the parts are separately manufactured and then assembled together. As a result of this, significant amounts of work have been devoted toward the development of new and improved one-piece dispensing closures.
Much of this development work has been directed toward the construction of one-piece dispensing closures which are constructed in such a manner as to include a lid mounted on or connected to a base or similar closure part in such a manner that the lid will not stay at rest in a position in which the lid partially blocks access to an opening through the clousure part or base.
It is not considered that an understanding of the present invention requires a detailed review of the various dispensing closures which have been developed so as to contain a lid which will automatically move toward either an open or closed position after having been manipulated to a position between these two positions and then released. Those prior structures which are closely related to the structures of the present invention are considered to be of a utilitarian, useful character. However, it is considered that these prior related structures which will operate in the manner indicated are comparatively disadvantageous for various different reasons.
Certain of such prior "automatic" type dispensing closures are constructed so that one or more functional or operative parts of such closures tend to be exposed in such a manner that there is a resonable possibility of damage to such parts during the installation of such closures on containers using capping equipment and so that there is a lesser continuing possibility of damage to such parts during handling and use of such closures. Some of such dispensing closures are also considered to be undesirable because they include various extending parts, such as posts, blades or the like which may be ojbectionable from an appearance standpoint or because of the possibility of accumulations around or adjacent to them. In general, such prior "automatic" type dispensing closures which preceded the present invention have been designed so that two and frequently more parts of such closures are of a "critical" character in that such parts must be designed with great care in order to obtain a desired manner or mode or operation.
As a result of these considerations and the possibility of patent infringement problems it is considered that there is a need for new and improved dispensing closures of the type indicated in the preceding discussion. More specifically it is considered there is a need for such closures which operate satisfactorily, which are capable of being easily installed without significant danger of damage, which have a minimum of parts, which are desirable because of their shape and configuration, and which are of such a character that they can be easily designed in accordance with standard design practice as hereinafter indicated.